Um Study Links Genetic Mutations To Depression

September 26, 2006|By Bob LaMendola Health Writer

University of Miami researchers reported new evidence Monday that clinical depression appears to be caused by inborn genetic mutations.

In a study published this week by the National Academy of Sciences, researchers showed patients with depression were twice as likely as well patients to have a mutation of a specific gene, known as PDE11A. The study also linked related genes to depression.

The gene's effects on the body might be counteracted by medications that are already on the market, such as Viagra, possibly offering doctors a new tool to treat depression, said Dr. Ma-Li Wong, a psychiatry professor and co-author of the study. She cautioned, however, that there is no proof that any drug would work in that way.

Research for years has identified genes involved in depression, but Wong said the new study is the first to make a link to an entire family of genes.

"In our biased opinion, this looks like a strong lead for future treatment," Wong said.

The study also found evidence that mutations of other PDE genes may signal which patients will succeed with the anti-depressant drugs fluoxetine (Prozac) and desipramine. Those with the mutations were four to nine times more likely to succeed with the drugs than were others in the study, although the authors said more research is needed to confirm the findings.

"If a marker would tell us who's likely to respond, that would be a big help," said Dr. Julio Licinio, a co-author and chairman of psychiatry. "Now, it's like a big guessing game. You don't know which drugs are going to work for which person."

The study compared 284 clinically depressed Mexican-Americans in Los Angeles with 330 others. Licinio said the evidence suggests the findings apply to all demographic groups.

The target of the study were genes controlling phosphodiesterase (PDE), a group of enzymes the body makes as signals to control key functions, Wong said.

Deficiencies in PDE have been connected to heart disease, asthma, inflammation and erectile dysfuntion.

In this case, patients with a mutation in the PDE11A gene were 2.1 times more likely to be depressed as other patients in the study, and those with a mutation in the PDE9A gene were 40 percent less likely to be depressed.

Bob LaMendola can be reached at blamendola@sun-sentinel.com or 954-356-4526 or 561-243-6600, ext. 4526.